//输入两棵二叉树A，B，判断B是不是A的子结构。（ps：我们约定空树不是任意一个树的子结构）
struct TreeNode {
	int val;
	struct TreeNode *left;
	struct TreeNode *right;
	TreeNode(int x) :
			val(x), left(nullptr), right(nullptr) {
	}
};
class Solution {
public:
    bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
    {
    	if(pRoot2 == nullptr || pRoot1 == nullptr)
    		return false;
		bool result = false;
    	if(pRoot1 -> val == pRoot2 ->val)
    		result = compareTreeNode(pRoot1,pRoot2);
    	if(!result)
    		result = HasSubtree(pRoot1->left,pRoot2);
    	if(!result)
			result = HasSubtree(pRoot1->right,pRoot2);
		return result;
    }

    bool compareTreeNode(TreeNode *pRoot1,TreeNode *pRoot2)
    {
    	if(pRoot1 ==nullptr)
    		return false;
    	if(pRoot2 == nullptr)
    		return true;
    	if(pRoot1->val != pRoot2->val)
    		return false;
    	return compareTreeNode(pRoot1->left,pRoot2->left)&&compareTreeNode(pRoot1->right,pRoot2->right);
    }
};
